Marking paint ball and method for making same

Abstract

A marking paint ball includes a shell made of non-water-soluble polymer material and having a substantially spherical shape. A marking paint composition is contained in the shell. The shell is made of an oxo-biodegradable material. A method for making such a ball is disclosed.

1. Marking paint ball comprising:
 a shell made of non-water-soluble polymer material and having a substantially spherical shape, and 
 a marking paint composition contained in said shell, 
 wherein the shell consists of an oxo-biodegradable polymer material which when oxidized in the presence of microorganisms is converted to carbon dioxide, water and a non-sterile biomass without generating toxic residues. 
 
     
     
       2. Ball according to  claim 1 , wherein the oxo-biodegradable polymer material is an oxo-biodegradable thermoplastic polymer. 
     
     
       3. Ball according to  claim 2 , wherein the oxo-biodegradable thermoplastic polymer is an oxo-biodegradable polyolefin. 
     
     
       4. Ball according to  claim 3 , wherein the oxo-biodegradable polyolefin is an oxo-biodegradable polyethylene. 
     
     
       5. Ball according to  claim 1 , wherein the oxo-biodegradable polymer material comprises a synthetic polymer and at least one transition metal salt. 
     
     
       6. Ball according to  claim 1 , wherein the shell has a thickness between 80 and 300 μm. 
     
     
       7. Ball according to  claim 6 , wherein the shell thickness is between 80 and 120 μm. 
     
     
       8. Ball according to  claim 1 , wherein the marking paint composition is water-based. 
     
     
       9. Ball according to  claim 8 , wherein the marking paint composition contains 40 to 60% water, 0 to 5% coloring substances and 20 to 40% binder. 
     
     
       10. Ball according to  claim 9 , wherein the marking paint further contains up to 5% sodium chloride. 
     
     
       11. Method for producing a marking paint ball comprising a shell containing a marking paint composition, comprising the following steps:
 providing two films of similar material; 
 arranging said films in an encapsulation unit comprising two molding drums, each comprising a drum cylinder wherein a plurality of hemispherical cavities are formed, said molding drums being arranged such that axes thereof are parallel and the drum cylinders are joined, said films feeding continuously in the encapsulation unit so as to arrive tangentially on the drum cylinders; 
 transforming the films into capsule portions having a substantially hemispherical shape by means of counter-rotating rotation of the molding drum cylinders, and the simultaneous introduction of the marking paint composition into said capsule portions; and 
 closing said capsule portions to form said shells filled with marking paint composition; and 
 the films being made of oxo-biodegradable non-water-soluble polymer material which when oxidized in the presence of microorganisms is converted to carbon dioxide, water and a non-sterile biomass without generating toxic residues, and 
 prior to the arrival of the films on the drum cylinders, said films are heated to a temperature between 90 and 140° C. 
 
     
     
       12. Method according to  claim 11 , wherein
 said films are made of oxo-biodegradable polyolefin, and 
 the heating temperature of said films, prior to the arrival thereof on the drum cylinders, is between 100 and 120° C. 
 
     
     
       13. Method according to  claim 12 , wherein said films are sheets made of monoaxially or biaxially-oriented polyolefin. 
     
     
       14. Method according to  claim 11 , wherein the method is devoid of any drying process following the thermoforming of the hemispheres. 
     
     
       15. Method according to  claim 11 , wherein the sheet of polymer material is a multi-layer sheet comprising a superposition of a plurality of single layers obtained by means of coextrusion or rolling.